1. Field of the Invention
This invention relates to a semiconductor device having a plurality of semiconductor chips mounted on one package and a production method thereof.
2. Description of the Related Art
Semiconductor devices of the type in which a plurality of semiconductor chips are mounted to one substrate, or of the type in which circuit components such as capacitors and resistors are mounted together with semiconductor chips on one substrate have been offered in the past as products that are compact in size and yet have versatile functions.
FIG. 6 of the accompanying drawings shows a structural example of a semiconductor device including a plurality of semiconductor chips 12 mounted to one substrate 10. FIG. 6(a) shows an example where the semiconductor chips 12 are mounted on both surfaces of the substrate 10. FIG. 6(b) shows an example where the semiconductor chips 12 are stacked and mounted on one of the surfaces of the substrate 10. FIG. 6(c) shows an example including a plurality of semiconductor chips 12 mounted on one of the surfaces of the semiconductor substrate 10. FIG. 6(d) shows an example where the semiconductor chips 12 are mounted on both surfaces of the substrate and a plurality of semiconductor chips 12 are further mounted on the surface of the substrate.
A wiring pattern is formed on the surface of the substrate 10. In all the examples shown in the drawings, the semiconductor chips 12 and the wiring pattern are electrically connected to one another by wire bonding. Needless to say, flip-chip bonding, TAB connection, and so forth, can be utilized, instead of wire bonding to electrically connect the semiconductor chips 12 and the wiring pattern.
When a plurality of semiconductor chips are mounted on the surface of the substrate 10 in the semiconductor devices of the types described above, the size of the substrate limits the number of semiconductor chips 12 that can be mounted. When the semiconductor chips 12 are stacked and mounted, too, it is not easy to mount a large number of semiconductor chips. When these semiconductor chips 12 and circuit substrates are mounted to one package in this way, the number of semiconductor chips 12 that can be mounted is limited by the method that merely mounts the semiconductor chips 12 on the substrate 10, and this method cannot yet provide a high integration density and multiple functions.
Therefore, a method that laminates wiring patterns, that are to be formed over the substrate, through electric insulating layers, and assembles the semiconductor chips inside the substrate has been proposed as a method of providing a higher integration density and multiple functions of semiconductor devices. FIG. 7 shows an example of such a method. Semiconductor chips 12 are buried into a resin substrate 14, wiring patterns 18 are laminated through electric insulating layers 16, and the wiring patterns 18 and the semiconductor chips 12 are electrically connected to give a semiconductor device.
Extremely thin semiconductor wafers have been produced in recent years, and semiconductor chips having a thickness of about 50 μm have been fabricated. Electric insulating layers for laminating wiring patterns have a thickness of about 100 μm. Therefore, semiconductor chips and circuit components can be buried and assembled into a package by using the thin-type semiconductor chips.